The invention relates to a tubular support body for bridging two vertebrae having two cages which are placed one within the other and are provided with cut-outs and which each has a support flange at the outer front surface.
Support bodies of this kind are implanted in the region of the intervertebral discs when the intervertebral discs themselves no longer withstand the stresses which the adjacent intervertebral discs exert on them and a support body is required as a fill-in.
Support bodies of this kind are often designed as cages which are filled with autologous bone chips prior to the implantation. The cut-outs in the cages are herein chosen in such a manner that the bone tissue is captive, but that a supply of the bone tissue takes place through the cutouts after the implantation at the same time.
The patent specification DE 195 04 867 shows support bodies which can be pushed together to their insertion length prior to implantation. This has the disadvantage that the required construction length must be very precisely determined in advance. The orthopaedist must therefore have an entire arsenal of components in the operating room in order to assemble one of a suitable size.
A different design is shown in EP-A-0 693 274 with adjustable threads which determine the length of a support body at a suitable height and are subsequently secured by screws which penetrate radially into the thread. An embodiment of this kind has the disadvantage that it can actually be fixed only once due to the damage which arises at the thread. Achieving a certain bias force on the securing screws is possible only via a plastic deformation of the threaded passages at the support body.